Airspace blog

Andy Sinclair, Head of Airspace Strategy and Engagement

The purpose of our blog is to update readers on airspace related activities and issues at Gatwick Airport and around the local area that may be of interest to our local communities and stakeholders. I plan to include updates on public aviation consultations, airspace and operational changes and the work of our Noise Management Board. If you want to know more about noise from planes or the airport or find out more about flightpaths of aircraft, then please use our specially developed Noiselab where you will find a raft of data and information.

Reduced night noise trial update - 25 September 2018

Back in March 2017, during the fifth NMB, an initiative was proposed to reduce the noise that aircraft make when arriving at Gatwick. The initiative, with the support of our communities, would involve running a ‘Reduced Night Noise’ (RNN) trial (between the hours of 01.30 to 05.00) to increase the height of low flying aircraft so the noise they make on the ground is reduced.

Based on the results of similar approaches at Schiphol and Dublin airports, it is expected the majority of residents who are currently overflown will experience less noise during the trial because the aircraft will be flying higher. It is also important to note that no more aircraft will fly at night than currently during any trial and that nobody will be newly overflown.

Discussions with the CAA and work by the NMB to bring the RNN to fruition continues and for a more detailed explanation about the proposed initiative, you can read our Q&As.

We have also noticed some recent speculation among local residents that a routine calibration test flight at Gatwick is a precursor to the RNN. Calibration checks of the Instrument Landing System are in fact a periodic safety requirement for all UK airports so are not linked to the proposed RNN.

The Instrument Landing System comprises of a radio beam and a signal that guides inbound aircraft to touchdown. The procedure involves making a series of approaches and breaking off without landing. This results in areas surrounding the airport being overflown during the calibration test flight. The checks are carried out at night when there is little traffic and because of this a light aircraft is used to minimise disturbance to the local community.

I will share further updates on the RNN once the initiative has been discussed at the next NMB.

Following an initial meeting in March, I met again with the CAA on 20 April to understand CAA requirements and to discuss options and next steps in relation to Route 4. Following the quashing of the CAA’s April 2017 decision by consent, we are working to revert the Route 4 conventional standard instrument departures (SIDs) to their position as they were before 7 April 2017. In support of this we are in the process of completing a comprehensive safety review. We plan to submit these changes, subject to CAA approval, on 15 June to allow implementation on 13 September, following the necessary changes to air traffic control systems and aeronautical publications.

This reversion to the previously published SIDs is not likely to result in any changes to the tracks flown by air traffic as almost all aircraft fly using the RNAV-1, or satellite navigation, based SIDs which have reverted to temporary SIDs pending redesign. A redesign of the Route 4 RNAV-1 SIDs will be necessary through the development of a new Route 4 Airspace Change Proposal, which we will commence in the coming months. The airport is focused on following the correct procedure taking into account the various relevant factors to achieve an end result as soon as possible. This required rigorous legal process does however mean that a final outcome is likely to take up to two years to achieve.

Alongside our communities, Gatwick wishes the issue to be resolved as soon as possible and will work closely with all parties, including through public consultation and the necessary technical and safety planning authorities, to ensure this happens.

Following the judgement to quash the CAA’s Route 4 Standard Instrument Departure routes Post Implementation Review in April 2017, I met with the CAA’s Head of Airspace Regulation to get a more detailed understanding of the judgement and what the CAA is asking Gatwick to do as a result of it.

Following that discussion, I have now written to the CAA to request a further meeting to discuss the process for the development and implementation of Route 4 RNAV SIDs. In essence, we need to simplify some of the complex technical aspects while ensuring we can manage change to deliver a timely solution in line with the intent of the Consent Order.

I also asked for details of the CAA investigation into the history of Route 4 and any supporting evidence which led the CAA to request that the Court quash its original decision. I intend to share this information with local communities and other involved stakeholders as part of the ongoing airspace change process.

We were pleased last month to see the operation of the first EasyJet New Engine Option or NEO from Gatwick. This marks the start of an exciting programme of aircraft fleet replacement for EasyJet which over time, will make a really important contribution to reducing noise. This is part of a wider programme with our aviation partners aimed at reducing noise in and around the airport.

Significant noise reduction

The A320 new engine option provides significant environmental benefits, for example, it will reduce noise by up to 50%; in terms of measured noise level - this is around 4dB on departure and 3dB on arrival.

To put this into context easyJet operates around 40% of the flights to and from Gatwick and so this development forms a very important part of our collective approach to reducing aviation noise. A number of other airlines that fly from Gatwick also have fleet replacement plans involving the A320 and the slightly larger A321 NEOs all of which will contribute to delivering environmental improvements.

Other noise management strategies

This together with other noise management strategies we are developing and deploying at Gatwick will contribute to improve aviation noise.

An example of a current initiative on a similar theme is a programme led by Gatwick in conjunction with the Noise Management Board to incentivise airlines to modify their aircraft to reduce airframe noise on the existing A320 series aircraft. Flight testing by Airbus has shown that the modification to the Fuel Over Pressure Protector or FOPP under the wing reduces noise by between 4dB and 11dB.

In October last year we wrote to all 128 airlines operating at Gatwick to let them know we would be introducing a new charging regime to encourage uptake of new and modified A320 aircraft.

Since being notified of this change BA and EasyJet – which account for 80% of all A320 flights – have modified 100% of their aircraft, which is extremely encouraging.

We are making improvements to our online noise lab, known as Casper. We continue to monitor the use and effectiveness of our complaints system and get feedback on it through a number of ways, including the NMB, the Noise and Track Monitoring Advisory Group and the Gatwick Airport Consultative Committee.

We have implemented a number of upgrades including optimising the complaint mapping tool so that it works from mobile devises and improving the availability of live flight data. I am also pleased to report that we are considering further improvements, including the possibility of introducing an automated telephone system. This would be linked directly to Casper to ensure that all complaints are logged in one single place.

The Noise Management Board (NMB) met again on 6 September to discuss the group’s work plan which, as mentioned in the last blog, now includes both arrivals and departures related projects.

GAL has commissioned TRAX (an external consultancy) to undertake a detailed report into issues on Routes 3 and 4 Standard Instrument Departures (SIDs). This work, in line with the recommendations of the CAA Route 4 Post Implementation Review, will consider whether some of the altitude restrictions on Routes 3 and 4 can be removed to allow aircraft to gain a higher altitude more quickly. It will also look at the feasibility of whether multiple departure routes could be used for Route 4 westerly departures, which would give respite and/or dispersion for affected residents.

Report scope

The work on Routes 3 and 4 is broken down into two parts. The first project will identify which air traffic routes impact or limit the operation of Gatwick SIDs on Routes 3 and 4. The output from this work will document:

The reasons for the existing initial altitude restrictions on both Route 3 (SAM/KENET) and Route 4 (DVR/ADMAG/LAM/CLN/BIG) departures

The actions required to enable a higher initial altitude

The feasibility and expected impact of making changes which will be used to inform next steps.

The second project - which will start after the report into raising the altitude restrictions is complete - is a study which explores multiple route options for runway 26, Route 4 departures. Once complete this project will document:

Constraints on the maximum lateral displacement of Route 4 (other routes i.e. Heathrow will probably limit how far apart routes can be placed)

Options using a higher navigational tolerance which may allow a wider number of design options

Many readers will be aware that the initial focus of Gatwick’s Noise Management Board (NMB) was the delivery of the recommendations made by the Independent Arrivals Review. As the majority of these recommendations have been now been delivered, the NMB’s scope of work has been extended to also include noise issues around aircraft departures. It was agreed at the NMB on 5 April that the new work plan being developed should define and prioritise work streams specifically focused on departures related issues.

With that in mind, we held an independently facilitated departures workshop with community representatives on 1 June 2017, to give us more insight into departures noise impacts and issues. This workshop built on feedback we had already received through the NMB and other meetings with a number of local community groups and councils. The outputs from these sessions were used as a basis to lead the discussion at an aviation industry workshop whose aim was to develop a programme of work to address the issues raised by communities.

The results of both workshops have been used to prioritise the NMB work plan for 2017/18 which now include both arrivals and departures activities. The workshop output will also help to shape our future airspace planning, for example following up on the CAA’s recommendations on Route 4.

The NMB work plan for the coming year will be formally agreed at the next meeting in September 2017.

Separately, we are also continuing to monitor the performance of the modified runway 08 Route 5 SIDs towards the east introduced on 30 March 2017. Gatwick is required by the CAA to monitor the revised design for six months after implementation and we are providing track, weather and complaint data to the CAA to help them assess whether the revised design has been successful.

Between 30 March and 31 May, Route 5 was used by 2225 aircraft achieving 99.74% route compliance. We received nine complaints attributable to Route 5 departures. The total number of complaints over the period received by Gatwick was 4438, of which 40 were from the postcode area in the vicinity of the route. For further information please see our Route 5 page.

NATS has recently submitted an Airspace Change Proposal (ACP) to the Civil Aviation Authority (CAA). The proposal will better separate Heathrow and Gatwick Standard Arrival Routes (STARs), which aircraft follow before they arrive into the holds from the south and west. You will see from the map below (on which Gatwick’s WILLO Hold is depicted by the solid red line) that NATS initially planned to route traffic along the coast, but the proposed route has now been designed further inland to more closely reflect the current STAR and to avoid flying over the towns along the south coast. By comparison to the initial design it will further enhance safety and allow for more efficient descent profiles – enabling aircraft to stay higher for longer and fly shorter distances.

Given the sensitivity to change in the patterns of aircraft flight paths, we want to draw your attention to this, though I should emphasise that these proposed changes, that only affected the published entry axis to HOLLY (the navigation waypoint to access the WILLO Hold), are at higher levels and there will be no discernible change to descent profiles or tracks over the ground. Also the change will make no difference to the location of aircraft operating at lower altitudes as they approach Gatwick.

Subject to CAA approval it is expected these changes will be implemented in November 2017. NATS will review performance to make sure aircraft are able to fly the new route correctly and there will be a CAA Post Implementation Review (PIR) after 12 months. More detail on the proposed changes can be found here on the CAA’s website:

If you would like any further information on this change, please contact Robin Clarke, the NATS Community Relations Manager, at public.enquiries@nats.co.uk

As part of our effort to improve consistency and transparency on airspace and noise related matters we have committed to increase communication of operational changes. Going forward, we will use this blog to provide more information about operational, as well as airspace changes, so that our local communities have the information needed to understand the impact of, and reasons for, any planned operational change. With that in mind, below are details around the formalisation of a tactical departures procedure.

Gatwick Airport will be assessing the procedure which, for short periods, will bias towards departing flights. This is a minor change in the pattern of daily departures traffic at Gatwick and standardises an existing way we operate during some busy periods. We intend to conduct an operational assessment of the procedure on a number of days from June 2017. We will monitor and review any impacts with the intent of adopting the procedure permanently.

There have been a number of airspace related consultations initiated by government over the past few months which I know have not been easy to follow. I have mentioned in the past the importance of contributing to these consultations as the policies that result will shape operations at Gatwick over the coming years. Below I've set out a summary of those consultations and - where Gatwick has responded - our contributions to those consultations.

Route 5

The amendment to our easterly departure routes designated as Route 5 has been in place since 30 March. We have provided the CAA with the first month of data and although only in operation for a few days, 632 aircraft have used the route with a high-level of track conformance.

Noise Management Board

Work in support of the Noise Management Board (NMB) is focussing on Fair and Equitable Dispersal and the drawing in of departures related noise issues into the NMB work plan for the coming year. We have held a number of meetings with local groups and councils, from which we have been able to draw on some useful insights and thinking and recognise consideration of the views and ideas expressed during these meeting in developing the NMB 2017/2018 work plan is essential.

Building on this work GAL has invited a range of community representatives to an NMB departures workshop on 1 June. Attendees will have the opportunity to raise issues and questions and to make suggestions about initiatives to reduce the effects of departures noise. This will be followed by a meeting with our industry partners to consider whether issues raised are captured by existing noise management initiatives or how we can develop the NMB work plan to incorporate community ideas.

A number of weeks have passed since my last update and there has been a lot going on during that period and so I thought that now might be a good time to provide a further update on the Government-led airspace related consultations as well as on a number of local airspace issues.

Gatwick specific issues

Route 4

Following the Post Implementation Review (PIR) of the runway 26 Route 4 RNAV 1 Standard Instrument Departures (SID) the CAA has concluded that the modified Route 4 SIDs achieve a satisfactory replication of the nominal track of the corrected conventional SID. The CAA has therefore decided to confirm the RNAV 1 SID designs currently published in the UK Aeronautical Information Publication (AIP) as permanent.

In its decision letter (CAP 1531) the CAA provided a series of suggested undertakings that we will study and draw into our work with the Gatwick Noise Management Board. The conclusion of the CAA deliberations and supporting data are published in full on the CAA website.

The CAA’s airspace change process in respect of Route 4 has now concluded.

Route 5

The amendment to our easterly Standard Instrument Departures contained within the Noise Preferential Route known as ‘Route 5’ came into effect on 30 March.

We have established a dedicated website where a briefing document detailing the requirements behind the amendment can be viewed as well as the mechanism for leaving feedback: http://www.gatwickairport.com/route5

Gatwick Airport will collate operational performance data and feedback statistics over a six month period and, as with Route 4, will provide this to the CAA for their consideration.

Route 2

In response to the CAA request that we modify our Route 2 RNAV SID design - with the aim of reducing ballooning around the turn towards the south - Gatwick submitted a revised design for the runway 08 SFD 4Z SID. However, the CAA has since concluded that the track keeping performance of departures on Route 2 around the first turn has improved. The CAA has therefore decided they no longer require Gatwick to modify the designs implemented in November 2013 and have amended the PIR conclusions accordingly.

The CAA’s airspace change process in respect of the Route 2 SID has now concluded.

16 February 2017

Department for Transport Night Flying Consultation

As many readers will be aware Gatwick Airport is a twenty-four hour operation and as such has a regime in place to govern night flying. This current night regime expires in October 2017. The Night Flight Restrictions consultation details the DfT’s proposals for a future five year regime at Gatwick, Heathrow and Stansted airports to replace existing system.

The DfT is proposing a cap set at existing levels for the number of night flights from Heathrow and Gatwick, and will end exemptions for almost 1,700 night flights operating out of Stansted. The DfT will also examine options for how we can better incentivise the use of quieter aircraft by reducing the noise each airport can make during the night.

The consultation and the related impact assessment is seeking views and evidence relating to DfT proposals that will inform the eventual decision on the restrictions to be introduced later this year.

The final output from the Consultation will not be known until after the National Policy Statement has been designated and then Government will issue the Strategy.

I hope that you will take the opportunity to examine the proposals as they are published and share details of these consultations with others who may be interested.

Route 4

As mentioned previously, frequent visitors to these pages will be familiar with the amendment introduced in May 2016 to the westerly departure ‘Route 4’. The monitoring period of the amendment ceased on 26 November 2016 and the Civil Aviation Authority continues to assess the operational data and the community feedback submitted by the airport. We expect the Civil Aviation Authority to make its final decision regarding Route 4 approximately four months after the cessation of the monitoring period, i.e. by March 2017. I will update this blog on any route 4 developments.

Amendment to Standard Instrument Departure Route 5

Gatwick Airport Ltd is required to amend the 08 CLACTON / DOVER Standard Instrument Departure routes that are used when the runway is operating in an easterly direction.

This requirement arises from the ‘Report of the CAA’s Post Implementation Review of the Implementation of RNAV-1 Standard Instrument Departures at Gatwick Airport.’ (CAA Report CAP1346).

The Noise Preferential Route associated with these departure routes is referred to as ‘Route 5’.

The map below illustrates the location of Route 5.

The amendment to Route 5 is intended to ensure departing aircraft follow the nominal centreline of the Noise Preferential Route (the blue shaded area on the map). Aircraft flying the current route design follow an easterly track in the southern portion of the Noise Preferential Route.

We have prepared a briefing document with more information about this amendment, which will come into effect on 30 March 2017.

23 December 2016

The six month monitoring period of the amendment to the Route 4 Standard instrument Departure (SID) routes came to an end on 26 November 2016. Since that time, we have been collating the remaining data and information and have now forwarded this to the Civil Aviation Authority for consideration.

Information forwarded to the Civil Aviation Authority incudes:

Monthly aircraft track dispersion plots.

Monthly aircraft track density plots.

Monthly aircraft altitudes maps.

Daily ‘METAR’ meteorological information at the aerodrome.

Details of operational issues arising from Gatwick Air Traffic Control and London Terminal Control at Swanwick.

Details of any operational issues raised by aircraft operators.

Plots showing the locations of residents providing feedback.

Copies of all feedback received from local communities.

Observations of the amendment

While this amendment has been unpopular in certain communities, our assessment of the route modification is that it has achieved what was required. The majority of aircraft have been restored to flying within the lateral confines of the Noise Preferential Route associated with Route 4 with c. 94% track-keeping compliance while simultaneously providing a degree of dispersal around the route’s turn; something that was particularly requested by the local communities.

Track-keeping

For comparative purposes, track-keeping conformance achieved on the ‘conventional’ (i.e. non-R-NAV1) SID during the period May-November 2013 was 92.6%. We are confident that the Route 4 R-NAV1 has delivered improved performance. Following the original R-NAV1 implementation during the period May-November 2015 traffic route conformance dropped to 62.06%. Track-keeping has significantly improved during this monitoring period with conformance reaching 93.95% over the period May-November 2016. In terms of air traffic movements (ATMs) although the number of aircraft flying the route during both periods was around the same – 19,792 (2015) and 19,722 (2016) – this reduced off track aircraft by 6315 ATMs.

Windy day SID

As part of the process to ensure sufficient operational compliance, Gatwick Airport Ltd initially considered whether an alternate R-NAV1 SID design option should be included to be used in periods of strong south-westerly wind conditions. It became clear that such an option, while feasible, could potentially be counterproductive in terms of material noise benefits for the communities overflown. This is because in order to maintain compliance with the parameters of the NPR, aircraft would have to fly at a speed that would require the use of flaps and a thrust setting that was likely to create more noise than would be the case if the aircraft was in a ‘clean’ configuration thus negating any perceived benefit from improved track keeping. This is especially relevant considering the existing levels of compliance are relatively high.

At the present time, we are minded to discontinue the ‘windy day’ SID proposal and have outlined our position on this matter to the CAA.

Route 4 statistics

During the monitoring period complaints received in respect of Route 4 were as follows:

Number of pieces of email feedback:

16,964

Number of individual email addresses:

1,863

Numbers of email addresses

Feedback email nos

Feedback %

50 individuals responsible for

5,731

33.78%

100 individuals responsible for

7,902

46.58%

250 individuals responsible for

11,824

69.70%

Horley overflight

Of the total number of complaints received, 4,858 (29% of the total) from 695 individuals (37% of the total), related to the overflight of Horley, as aircraft were vectored from the SID.

After the adoption of this amendment, levels of vectored traffic leaving Route 4 and over flying Horley increased from historical levels of approximately 1-3% to a high of 8-9%. This is clearly an important issue but one which we consider to be separate from the route design itself. Working closely with NATS this problem has been addressed through a controller education programme as a result of which the number of Horley overflights have progressively declined since the problem was first identified.

For comparison the first 2 weeks of September overflights were measured at 7.36% and 6.67% respectively but the first 2 weeks of December were 0 and 0.71%. We will continue to monitor the numbers of Horley overflights and work with NATS to ensure the highest possible level of compliance.

Making complaints

The dedicated Route 4 email address is no longer monitored and will shortly be closed down therefore should individuals still wish to register noise complaints, they can do so via our dedicated noise complaint tool, Casper.

Information transparency

Route 4 performance data and a summary of feedback received will be available on our website in the early new year.

Finally, the evaluation of the data and the Civil Aviation Authority decision process may take three to four months. I have asked the Civil Aviation Authority to keep me advised of any changes in timescale or in the decision making process in order that I can keep you informed via this blog.

11 November 2016

The six months monitoring period of the amendment to Route 4 ends at 23:59 on 26 November 2016. As I have previously outlined, the Civil Aviation Authority (CAA) has been receiving monthly data packages from Gatwick Airport regarding route performance and feedback received, this activity however will cease with the end of the monitoring period at which time we will forward our final data package to the CAA and publish a data summary to this blog.

We will continue to monitor Route 4 performance in common with all other departure routes from Gatwick Airport and report accordingly in our Flight Performance Team reports to the Noise and Track Monitoring Advisory Group and the Gatwick Airport Consultative Committee; details of which are available online.

The CAA has undertaken to evaluate the data and decide whether the amendment has been a success or otherwise approximately three to four months after the end of the monitoring period.

After the cessation of the monitoring period:

The current amendment to Route 4 will remain in place at least until we hear from the CAA. This is because the route flown over the previous six months is not a trial but an amendment as required in the CAA Post Implementation Review. Should the CAA deem this amendment to be unsuccessful, it would be at that stage when we would consider other options available.

Should the airport be required to return to a conventional navigation procedure in the event the CAA deems the amendment to be unsuccessful, this would not be a permanent solution but would only be in place until alternative solutions are developed. This is because Performance Based Navigation (PBN) Standard Instrument Departure routes are UK CAA policy under international implementation policies and are expected to be mandated in terminal airspace from 2017.

The Route 4 dedicated email address will close at 23:59 on 26 November 2016. After this time, the method for registering noise complaints will be via our dedicated noise website

Route 4 Statistics

Total number of Route 4 specific complaints up to 11 November 2016: 15,689.

Track keeping broken down by the individual Route 4 Standard Instrument Departure (SID) Routes is provided in the table below:

31 October 2016

During September Gatwick Airport operated the westerly runway for 84% of the month with 4,409 aircraft departing via Route 4 with a track keeping rate of 91.35%. Since the route amendment was introduced in May 2016 the average track keeping achievement from May to September has been 97.87%. The Flight Performance Team at Gatwick continues to engage with our airline and industry stakeholders to improve this as much as possible.

There have been notable fluctuations in track keeping, for example on the 24th September there were 50 track deviations from Route 4 as aircraft were ‘ballooning’ outside of the NPR. The Met Office figures for the Gatwick area on this date revealed winds at 3,000ft to be generally 180-200° 26-29 knots, increasing to 29-33 knots later that day. As we expected, strong winds can affect track keeping performance on this Route.

We continue to receive a substantial amount of feedback from local communities regarding Route 4. Sometimes this is not straightforward to interpret as we receive Route 4 related feedback even on those days when the airport is operating on the easterly runway. An example of this is the period 4 - 14 October during which we were operating on the easterly runway (so Route 4 was not in use) yet we received a volume of Route 4 specific feedback consistent with periods when the route was in use.

Horley overflight

We are acutely aware that overflight of the town, as published in the UK Aeronautical Information Publication, is expressly prohibited.

Aircraft that overfly Horley have invariably been ‘vectored’ away from Route 4 by the air traffic controllers at the NATS Control Centre at Swanwick. The practice of vectoring is not new but prior to the amendment currently in force, as the main swathe of traffic was further north than it presently is, aircraft vectored at the same stage of flight avoided Horley.

Levels of traffic being vectored after a Route 4 departure unnecessarily over flying Horley have increased from historical levels of approximately 1-3% to a high of 8-9%.

Since this increase was noted, all air traffic controllers at Swanwick who have duties relating to Gatwick departures have been briefed to avoid overflying Horley and received new guidance regarding vectoring as to when and how it should now take place, taking into account the amendment. Our initial impression is that this is now having some success as there is a more recent downward trend in Horley overflights; we will continue to monitor this matter closely and to do what we can to ensure that NATS stays vigilant on the subject.

Gatwick Airport will continue to provide the CAA with data throughout the monitoring period for this route, which will end on November 26. We expect the CAA to make and publish its decision within three to four months of the end of the monitoring period.